KMT and KMTA lock nuts are locked on the shaft (sleeve) by friction. The friction, and therefore the loosening torque, varies as a result of the accuracy of the tightening torque of the grub screw, the surface finish of the shaft thread, the amount of lubricant on the thread, etc. KMT and KMTA lock nuts should be properly mounted to threads that are dry or only have a minimum amount of lubricant on them.

Providing that they are properly mounted to a dry or minimally lubricated thread, experience has shown that SKF KMT and KMTA lock nuts have sufficient locking for typical super-precision and general rolling bearing applications.